Final answer:
The clouds described as "artist's brushes" or "mare's tails" belong to the cirrus cloud family.
Step-by-step explanation:
The clouds described as "artist's brushes" or "mare's tails" belong to the Cirrus cloud family. Cirrus clouds are high-level clouds that form above 20,000 feet in the atmosphere. They are usually thin, wispy, and have a fibrous or feathery appearance, which is why they are often compared to artist's brushes or mare's tails.
Cumulonimbus clouds are large, towering clouds associated with thunderstorms, stratus clouds are low-level, uniform clouds that often cover the sky like a blanket, and altostratus clouds are mid-level clouds that are gray or blue-gray and often indicate the approach of a warm front or a storm system.